Larvae of lepidopterous insects cause millions of dollars of damage each year to agricultural crops grown for food and fiber production. While chemical insecticides such as chlorinated hydrocarbons, organophosphorus compounds, carbamates, and synthetic pyrethroids are conventionally used to control these insects, most species are broadly and highly resistant to chemical insecticides due to the continued reliance upon such substances by producers in order to prevent crop damage and consequent economic losses.
Application of these largely ineffective chemicals have significant impact upon the environment in which they are placed. In addition to environmental pollution, use of chemical insecticides create potential health hazards for agricultural workers and consumers. The problem of residues on consumer products and water quality present major drawbacks. Detrimental effects of these chemical insecticides on nontarget species often result in secondary pest outbreaks. Moreover, such chemicals are often phytotoxic to exposed plants.
Because of the problems associated with the use of chemical pesticides, safer and more effective methods of controlling insect pests are essential for continued agricultural production. While biological control agents are a reasonable alternative to chemical pesticides, none have been identified as being commercially feasible for controlling lepidopterous pests by direct activity against the egg stage. Bacillus thuringenis, for example, is an biological control agent designed specifically as an insecticide for control of certain leaf-eating caterpillars (Lepidoptera). The active ingredient is a stomach poison and, as such, must be eaten by the larvae to be effective. Larvae of lepidopterous insects must, therefore, be actively feeding on treated exposed plant parts.
Recently the development of mycoinsecticides have been directed towards specific insects such as Bemisia tabaci. No mycoinsecticide has, however, been heretofore identified as having ovicidal activity.